This was a near-perfect fit for my Harley Benton TE-70 Black Paisley, I had to sand maybe a quarter of a millimeter on each end. The height was great on each string. I've had luthiers do a worse job.
Tuning stability improved dramatically. I also changed the string tees, which are also a factor in string binding during bending. The Harley Benton whose only issue was tuning stability now holds tune like a trained golden retriever dependably holds its own leash. Good girl.
I could be kidding myself since I didn't do a before and after recording to compare, but the tone seems better and the sustain longer. This mirrors my experience using a Graph Tech String Saver nut on a hollowbody archtop, so I think it's real.
I've only had it for a few days, so I can't speak about its durability. Other reviews suggested it can be an issue. I wouldn't have a problem replacing it once every two years if necessary.
I think this part is a cheap upgrade pretty much everyone should do.